This invention is directed to novel copper salts of sulfurized fatty acids and to their use in various organic compositions such as lubricants and other such material normally subject to oxidative degradation, containing a minor amount sufficient to impart antioxidant characteristics thereto of said sulfurized copper salts.
In a more particular aspect this invention is directed to the above referred to novel sulfurized fatty acid salts and lubricant compositions thereof. The lubricating oils are oils of lubricating viscosity as basestocks or hydrocracked lubricating oils or oils of lubricating viscosity adapted for use as hydraulic oils, various automotive oils, transmission fluids, waxes and greases and other solid or liquid forms requiring the presence of stabilizing agents to inhibit oxidative degradation. These oils may be derived from mineral oils or fractions thereof or synthetic oils or as mixtures of mineral and synthetic oils.
The use of sulfur compounds such as thioesters, dithiocarbamates, dithiophosphates, sulfurized fatty esters, and sulfurized olefins, have been well known for their antioxidant properties as well as their antiwear, EP characteristics in a variety of products.
The use of copper carboxylates such as copper oleate has been reportedly used as an antioxidant in European Pat. No. 92946 and in British Pat. No. 2,056,482 as an engine oil antioxidant.
The use of carboxylates as antirust and antirust and anticorrosion additive in lubricants have been well documented and include derivatives of oleic acid and oleoyl sarcosine.
The use of copper thiobis/alkylphenols as antioxidant additives has been described in U.S. Pat. No. 4,225,448.
It has now been found that the use of these new sulfurized fatty acid copper salts provide exceptional multifunctional antioxidant activity, anticorrosion, antiwear, and EP properties. The antioxidant activity demonstrated is greater than that reported for corresponding copper carboxylates or sulfur containing compounds.
These remarkable benefits are also expected for a variety of synthetic and mineral oil based lubricants. To the best of our knowledge, these compositions have not been previously used as antioxidants in lubricating oils, greases, plastics or fuel applications.
None of the foregoing, however, disclose lubricant compositions containing the novel multifunctional sulfurized fatty acid derivatives described in accordance with the present invention.